Conventionally, in the field of manufacture of a semiconductor device or the like, a plasma processing apparatus using inductively coupled plasma (ICP) has been known as an apparatus for performing, e.g., a film forming process or an etching process on a substrate such as a semiconductor wafer.
As a processing gas supply structure of the plasma processing apparatus using ICP, there is known a processing gas supply structure having a ring disposed in a processing chamber and provided with a multiple number of nozzles along the circumference of the ring, and supplying a processing gas while discharge positions of the nozzles toward the substrate are varied by rotating the ring in opposite directions alternately (see, for example, Patent Document 1).
Patent Document 1: Japanese Patent Laid-open Publication No. 2000-248364
In the plasma processing apparatus using ICP, the processing gas supply structure needs to be installed so as not to block an electromagnetic field induced from a high frequency antenna provided outside the processing chamber. Thus, basically, positions for discharging the processing gas have been limited to those corresponding to a central portion and a periphery of the substrate. In such a case, however, a processing gas cannot be properly supplied to meet a required processing performance.